Exodus 3:2-4 New International Version (NIV)
2 There the angel of the Lord appeared to him in flames of fire from within a bush.Moses saw that though the bush was on fire it did not burn up. 3 So Moses thought, “I will go over and see this strange sight—why the bush does not burn up.”
4 When the Lord saw that he had gone over to look, God called to him from within the bush, “Moses! Moses!”
And Moses said, “Here I am.”
So, Moses sees a burning bush and goes over to it to see what it was all about. It got his attention. He was curious. Many other people in the Bible experienced God in visible and not necessarily human form. Abraham saw a smoking fire pot and a flaming torch. Jacob wrestled with a man. When the Hebrews were delivered from Egypt, the entire nation was lead by a visible pillar of cloud by day and a visible pillar of fire by night. That must have been one gigantic flashlight for the entire nation. God makes appearances to encourage, to guide, and to prove his reliability of his Word and promises. How has God gotten your attention? I know for myself, it has been an audible voice giving me clear and concise direction and encouragement. Remember, when God gets your attention, his message to you will never go against his character or Word. Test all with his Word. I know that when he has spoken to me, I know his voice, and his voice is comforting. He has given me clear, concise, Godly wisdom to guide me and encourage me.